find the two largest values in a multidimensional list and discard other elements in matlab

main.m
% example multidimensional list
list = [1 2 3; 4 5 6; 7 8 9];

% flatten the list
flat_list = list(:);

% sort the flattened list in descending order
sorted_list = sort(flat_list, 'descend');

% pick the first two elements from the sorted list
top_two = sorted_list(1:2);

% create a logical index for elements less than the top two
less_than_top_two = flat_list < top_two(2);

% set the elements less than the top two to zero
flat_list(less_than_top_two) = 0;

% reshape the flattened list to the original dimensionality of the list
new_list = reshape(flat_list, size(list));
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